#include <bits/stdc++.h>
using namespace std;
vector<pair<int, int> > T[55];
int C[55];
int main() {
  int bottles, w, cups;
  scanf("%d%d%d", &bottles, &w, &cups);
  for (int i = 0; i < cups; ++i) {
    C[i] = bottles;
  }
  int c = 0;
  for (int i = 0; i < bottles; i++) {
    int amount = cups;
    int cnt = 0;
    while (amount > 0) {
      if (C[c] == 0)
        c++;
      else {
        int p = min(C[c], amount);
        C[c] -= p;
        amount -= p;
        T[c].push_back(pair<int, int>(i, p));
        cnt++;
        if (cnt > 2) {
          printf("NO\n");
          return 0;
        }
      }
    }
  }
  printf("YES\n");
  for (int i = 0; i < cups; ++i) {
    for (int j = 0; j < T[i].size(); ++j) {
      printf("%d %.6lf ", T[i][j].first + 1,
             (T[i][j].second * w / (double)cups));
    }
    printf("\n");
  }
  return 0;
}
