#include <bits/stdc++.h>
using namespace std;
double n, w, m;
vector<pair<int, double> > ans[100];
int main() {
  scanf("%lf%lf%lf", &n, &w, &m);
  double each = n * w / m;
  int id = 0;
  double last = 0;
  for (int i = 1; i <= m; i++) {
    double sum = each;
    if (each + 0.00001 < last) {
      printf("NO\n");
      return 0;
    }
    if (last > 0.00001) {
      ans[i].push_back(make_pair(id, last));
      sum -= last;
      last = 0;
    }
    while (sum >= w) {
      ans[i].push_back(make_pair(++id, w));
      sum -= w;
    }
    if (sum > 0.00001) {
      ans[i].push_back(make_pair(++id, sum));
      last = w - sum;
    }
  }
  printf("YES\n");
  for (int i = 1; i <= m; i++) {
    for (int j = 0, z = ans[i].size(); j < z; j++)
      printf("%d %.6lf ", ans[i][j].first, ans[i][j].second);
    printf("\n");
  }
}
