#include <bits/stdc++.h>
using namespace std;
const int mx1 = 55;
const int mx2 = 505;
const int mx3 = 1005;
const int mx4 = 30005;
const int mx5 = 100005;
const int mx6 = 1000005;
int _toggle(int N, int pos) { return N = N ^ (1 << pos); }
int _set(int N, int pos) { return N = N | (1 << pos); }
int _reset(int N, int pos) { return N = N & ~(1 << pos); }
bool _check(int N, int pos) { return (bool)(N & (1 << pos)); }
bool _upper(char a) { return a >= 'A' && a <= 'Z'; }
bool _lower(char a) { return a >= 'a' && a <= 'z'; }
bool _digit(char a) { return a >= '0' && a <= '9'; }
int dx[] = {1, -1, 0, 0, -1, -1, 1, 1};
int dy[] = {0, 0, 1, -1, -1, 1, -1, 1};
map<int, double> ans[mx1];
double n, m, w, _fill[mx1], eps = 1e-8;
stack<pair<int, double>> st;
int cnt[mx1];
void solve() {
  cin >> n >> w >> m;
  double mx = n * w / m;
  for (int i = 1; i <= n; i++) {
    st.push({i, w});
  }
  while (!st.empty()) {
    int id = st.top().first;
    double now = st.top().second;
    st.pop();
    for (int i = 1; i <= m; i++) {
      if (mx - _fill[i] > eps) {
        double add = min(now, mx - _fill[i]);
        _fill[i] += add;
        now -= add;
        ans[i][id] += add;
        cnt[id]++;
        break;
      }
    }
    if (now > eps) {
      st.push({id, now});
    }
  }
  for (int i = 1; i <= n; i++) {
    if (cnt[i] > 2) {
      cout << "NO\n";
      return;
    }
  }
  cout << "YES\n";
  for (int i = 1; i <= m; i++) {
    for (auto j : ans[i]) {
      cout << j.first << ' ';
      cout << fixed << setprecision(8) << j.second << ' ';
    }
    cout << '\n';
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int tc = 1;
  while (tc--) {
    solve();
  }
}
