diff --git a/ex-1/main.c b/ex-1/main.c
index 293e052..112fd23 100644
--- a/ex-1/main.c
+++ b/ex-1/main.c
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <math.h>
 #include <gsl/gsl_randist.h>
 #include <gsl/gsl_statistics_double.h>
@@ -15,12 +16,24 @@
  * distribution.
  */
 int main(int argc, char** argv) {
+  size_t samples = 50000;
+
+  /* Process CLI arguments */
+  for (size_t i = 1; i < argc; i++) {
+    if (!strcmp(argv[i], "-n")) samples = atol(argv[++i]);
+    else {
+      fprintf(stderr, "Usage: %s -[hn]\n", argv[0]);
+      fprintf(stderr, "\t-h\tShow this message.\n");
+      fprintf(stderr, "\t-n N\tThe size of sample to generate. (default: 50000)\n");
+      return EXIT_FAILURE;
+    }
+  }
+
   // initialize an RNG
   gsl_rng_env_setup();
   gsl_rng *r = gsl_rng_alloc(gsl_rng_default);
 
   // prepare histogram
-  size_t samples = 50000;
   double* sample = calloc(samples, sizeof(double));
   double min = -10;
   double max =  10;