#include <bits/stdc++.h>
using namespace std;
int r[100], ans[100][100][2];
int main() {
  int n, w, m, s, i, j;
  scanf("%d%d%d", &n, &w, &m);
  if (m > n * 2) {
    printf("NO\n");
    return 0;
  }
  s = 0;
  for (i = 1, j = 1; i <= n; i++) {
    s += m;
    if (s >= n) {
      s -= n;
      r[j]++;
      ans[j][r[j]][0] = i;
      ans[j][r[j]][1] = m - s;
      j++;
      if (s > 0) {
        if (s > n) break;
        r[j]++;
        ans[j][r[j]][0] = i;
        ans[j][r[j]][1] = s;
        if (s == n) {
          j++;
          s = 0;
        }
      }
    } else {
      r[j]++;
      ans[j][r[j]][0] = i;
      ans[j][r[j]][1] = m;
    }
  }
  if (i <= n) {
    printf("NO\n");
    return 0;
  }
  printf("YES\n");
  for (i = 1; i <= m; i++) {
    for (j = 1; j <= r[i]; j++)
      printf("%d %lf ", ans[i][j][0], ans[i][j][1] * 1.0 * w / m);
    printf("\n");
  }
}
