#include <iostream>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <string>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <tuple>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cassert>
#include <cstdint>
#include <numeric>
#include <bitset>
#include <functional>

using namespace std;

using ll =  long long;
using Pll = pair<ll, ll>;
using Pii = pair<int, int>;

constexpr ll MOD = 1000000007;
constexpr long double EPS = 1e-10;
constexpr int dyx[4][2] = {
    { 0, 1}, {-1, 0}, {0,-1}, {1, 0}
};

ll gcd(ll a, ll b){
    if(b == 0) return a;
    else return gcd(b, a%b);
}

ll lcm(ll a, ll b)  {
    return a / gcd(a, b) * b;
}
int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    int a, b, c;
    cin >> a >> b >> c;

    int l = lcm(a, b);
    int holidays = 0;
    for(int i=0;i<l;++i) {
        if(i % b < c) ++holidays; 
    }
    cout << setprecision(10) << fixed << double(holidays) / double(l/a) << endl;
}