#include <bits/stdc++.h>
using namespace std;
const int N = 200020;
const double eps = 1e-8;
int main() {
  int n, m;
  double w;
  scanf("%d %lf %d", &n, &w, &m);
  if (n < m && n % (m - n) != 0) {
    printf("NO");
    return 0;
  }
  printf("YES\n");
  double tot = (double)n * w / m;
  int temp = 0;
  int now = 1;
  for (int i = 1; i <= m; i++) {
    int all = n;
    if (temp != 0) {
      printf("%d %.12lf ", now++, w / m * (m - temp));
      all -= (m - temp);
      temp = 0;
    }
    while (all >= m) {
      all -= m;
      printf("%d %.12lf ", now++, w);
    }
    if (all) {
      printf("%d %.12lf ", now, w / m * all);
      temp = all;
    }
    printf("\n");
  }
  return 0;
}
