diff --git a/ex-2/fancier.c b/ex-2/fancier.c
index a08e315..c2bc256 100644
--- a/ex-2/fancier.c
+++ b/ex-2/fancier.c
@@ -3,6 +3,7 @@
 #include <stdarg.h>
 #include <math.h>
 #include <gmp.h>
+#include <time.h>
 
 /* The Euler-Mascheroni constant is here computed to
  * arbitrary precision using GMP rational numbers
@@ -12,8 +13,8 @@
  *
  * with:
  *
- *    A(N) = Σ_(k = 1)^(k_max) (N^k/k!) * H(k)
- *    B(N) = Σ_(k = 0)^(k_max) (N^k/k!)
+ *    A(N) = Σ_(k = 1)^(k_max) (N^k/k!)² * H(k)
+ *    B(N) = Σ_(k = 0)^(k_max) (N^k/k!)²
  *    C(N) = 1/4N Σ_(k = 0)^(2N) ((2k)!)^3/((k!)^4*(16N))^2k
  *    H(k) = Σ_(j = 1)^(k) (1/k), the k-th harmonic number
  *
@@ -332,9 +333,13 @@ void a_series(mpq_t rop, size_t N) {
   mpz_inits(fact, power, stop, NULL);
   mpz_set_ui(stop, N);
 
+  mpz_set_ui(fact, 1);
+  mpz_set_ui(power, 1);
   for (size_t k = 0; k < 5*N; k++) {
-    mpz_fac_ui(fact, k);
-    mpz_pow_ui(power, stop, k);
+    if (k > 0) {
+      mpz_mul_ui(fact, fact, k);
+      mpz_mul(power, power, stop);
+    }
 
     mpq_set_z(term, power);
     mpq_set_z(factq, fact);
@@ -365,9 +370,13 @@ void b_series(mpq_t rop, size_t N){
   mpz_inits(fact, power, stop, NULL);
   mpz_set_ui(stop, N);
 
+  mpz_set_ui(fact, 1);
+  mpz_set_ui(power, 1);
   for (size_t k = 0; k < 5*N; k++) {
-    mpz_fac_ui(fact, k);
-    mpz_pow_ui(power, stop, k);
+    if (k > 0) {
+      mpz_mul_ui(fact, fact, k);
+      mpz_mul(power, power, stop);
+    }
 
     mpq_set_z(term, power);
     mpq_set_z(factq, fact);
@@ -388,25 +397,29 @@ void b_series(mpq_t rop, size_t N){
 /* C series */
 void c_series(mpq_t rop, size_t N) {
   mpq_t sum, term, stop2, fact2q;
-  mpz_t fact1, fact2, power, stop1;
+  mpz_t fact1, pfact1, fact2, pfact2, power, stop1;
 
   mpq_inits(sum, term, stop2, fact2q, NULL);
-  mpz_inits(fact1, fact2, power, stop1, NULL);
+  mpz_inits(fact1, pfact1, fact2, pfact2, power, stop1, NULL);
   mpq_set_ui(stop2, 4*N, 1);
 
+  mpz_set_ui(fact1, 1);
+  mpz_set_ui(fact2, 1);
+  mpz_set_ui(stop1, 1);
+
   for (size_t k = 0; k <= 2*N; k++) {
-    mpz_fac_ui(fact1, 2*k);
-    mpz_pow_ui(fact1, fact1, 3);
+    if (k > 0) {
+      mpz_mul_ui(fact1, fact1, 2*k * (2*k - 1));
+      mpz_mul_ui(fact2, fact2, k);
+      mpz_mul_ui(stop1, stop1, 16*N);
+      mpz_mul_ui(stop1, stop1, 16*N);
+    }
+    mpz_pow_ui(pfact1, fact1, 3);
+    mpz_pow_ui(pfact2, fact2, 4);
+    mpz_mul(pfact2, pfact2, stop1);
 
-    mpz_fac_ui(fact2, k);
-    mpz_pow_ui(fact2, fact2, 4);
-
-    mpz_set_ui(stop1, 16*N);
-    mpz_pow_ui(stop1, stop1, 2*k);
-    mpz_mul(fact2, fact2, stop1);
-
-    mpq_set_z(term, fact1);
-    mpq_set_z(fact2q, fact2);
+    mpq_set_z(term, pfact1);
+    mpq_set_z(fact2q, pfact2);
 
     mpq_div(term, term, fact2q);
     mpq_add(sum, sum, term);
@@ -417,7 +430,7 @@ void c_series(mpq_t rop, size_t N) {
 
   // free memory
   mpq_clears(sum, term, stop2, fact2q, NULL);
-  mpz_clears(fact1, fact2, power, stop1, NULL);
+  mpz_clears(fact1, pfact1, fact2, pfact2, power, stop1, NULL);
 }
 
 
@@ -467,20 +480,48 @@ int main(int argc, char** argv) {
   // number of decimal places
   size_t D = atol(argv[1]);
   // number of terms
-  size_t N = floor(1.0/4 * log(10) * (double)D);
+  size_t N = 10 + floor(1.0/8 * log(10) * (double)D);
+
+  fprintf(stderr, "[main] N: %ld\n", N);
 
   /* calculate series */
   mpq_t A, B, C;
   mpq_inits(A, B, C, NULL);
+
+  clock_t begin, end;
+  double time_a, time_b, time_c, time_log;
+
+  begin = clock();
   a_series(A, N);
+  end = clock();
+  time_a = (double)(end - begin)/CLOCKS_PER_SEC;
+  fprintf(stderr, "[main] a series time: %gs\n", time_a);
+
+  begin = clock();
   b_series(B, N);
+  end = clock();
+  time_b = (double)(end - begin)/CLOCKS_PER_SEC;
+  fprintf(stderr, "[main] b series time: %gs\n", time_b);
+
+  begin = clock();
   c_series(C, N);
+  end = clock();
+  time_c = (double)(end - begin)/CLOCKS_PER_SEC;
+  fprintf(stderr, "[main] c series time: %gs\n", time_c);
 
   /* calculate γ... */
   mpq_t gamma, corr, logn;
   mpq_inits(gamma, corr, logn, NULL);
 
+  begin = clock();
   mpq_log_ui(logn, N, D);
+  end = clock();
+  time_log = (double)(end - begin)/CLOCKS_PER_SEC;
+  fprintf(stderr, "[main] log(n) time: %gs\n", time_log);
+
+  fprintf(stderr, "[main] total time: %gs\n",
+          time_a + time_b + time_c + time_log);
+
   mpq_div(gamma, A, B);
   mpq_div(corr, C, B);
   mpq_div(corr, corr, B);
@@ -493,15 +534,14 @@ int main(int argc, char** argv) {
   mpq_sub(diff, gamma, exact);
 
   /* print results */
-  size_t d = D+1 > 50 ? 50 : D+1;
+  size_t d = D+1 > 100 ? 100 : D+1;
 
-  fprintf(stderr, "[main] N: %ld\n", N);
   mpq_fprintf(stderr, d, "[main] approx:\t%q...\n", gamma);
   mpq_fprintf(stderr, d, "[main] exact:\t%q...\n",  exact);
   mpq_fprintf(stderr, d, "[main] diff:\t%q...\n",   diff);
   mpq_fprintf(stderr, d, "[main] digits:\t%q\n",    indicator);
 
-  mpq_fprintf(stdout, D+1, "%q\n", gamma);
+  mpq_fprintf(stdout, D, "%q\n", gamma);
 
   // free memory
   mpq_clears(A, B, C, gamma, corr, logn,