#include <bits/stdc++.h>
const double eps = (1e-10);
using namespace std;
int dcmp(double a, double b) {
  return fabs(a - b) <= eps ? 0 : (a > b) ? 1 : -1;
}
long long getBit(long long num, int idx) { return ((num >> idx) & 1ll) == 1ll; }
long long setBit1(long long num, int idx) { return num | (1ll << idx); }
long long setBit0(long long num, int idx) { return num & ~(1ll << idx); }
long long flipBit(long long num, int idx) { return num ^ (1ll << idx); }
int countNumBit1(long long mask) {
  int ret = 0;
  while (mask) {
    mask &= (mask - 1ll);
    ++ret;
  }
  return ret;
}
double M[59], W[59];
vector<vector<pair<int, double>>> ans(59);
int main() {
  int n, m, w;
  cin >> n >> w >> m;
  double av = ((w * n) + 0.0) / m;
  for (int i = 0; i < n; i++) W[i] = w;
  for (int i = 0; i < m; i++) M[i] = av;
  int goo = m;
  for (int i = 0, j = 0;;) {
    if (i == n) break;
    if (dcmp(W[i], M[j]) == 1 && W[i] != w) {
      cout << "NO\n";
      return 0;
    } else if (dcmp(W[i], M[j]) == 1 && W[i] == w) {
      ans[j].push_back(make_pair(i + 1, M[j]));
      W[i] -= M[j];
      M[j] = 0;
      j++;
    } else if (dcmp(W[i], M[j]) == 0) {
      ans[j].push_back(make_pair(i + 1, W[i]));
      M[j] = 0;
      W[i] = 0;
      i++;
      j++;
    } else if (W[i] < M[j]) {
      ans[j].push_back(make_pair(i + 1, W[i]));
      M[j] -= W[i];
      W[i] = 0;
      i++;
    }
  }
  cout << "YES\n";
  for (int j = 0; j < m; j++) {
    for (int i = 0; i < ((int)(ans[j]).size()); i++)
      cout << fixed << setprecision(7) << ans[j][i].first << " "
           << ans[j][i].second << " ";
    cout << endl;
  }
}
