#include <bits/stdc++.h>
using namespace std;
double memo[2005][2005];
int N, P, T;
double rec(int cur, int remainT) {
  if (remainT == 0) return cur;
  if (cur == N) return N;
  if (memo[cur][remainT] != -1) return memo[cur][remainT];
  double ans = 0;
  ans += (double)P / 100 * rec(cur + 1, remainT - 1);
  ans += (double)(100 - P) / 100 * rec(cur, remainT - 1);
  return memo[cur][remainT] = ans;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  char c;
  int a, b;
  cin >> N >> a >> c >> b >> T;
  P = a * 100 + b;
  for (int i = 0; i < 2005; i++)
    for (int j = 0; j < 2005; j++) memo[i][j] = -1;
  cout << fixed << setprecision(10) << rec(0, T) << endl;
  return 0;
}
