#include <bits/stdc++.h>

using namespace std;

const int MOD = 1e9+7;

typedef long long ll;

template<class T> T sum(T x) { return x; }
template<class H, class... T> H sum(H h, T... t) {
    H ans = h+sum(t...);
    if (ans >= MOD) ans -= MOD;
    else if (ans < 0) ans += MOD;
    return ans;
}
template<class T> ll mul(T x) { return x; }
template<class H, class... T> ll mul(H h, T... t) {
    return h*ll(mul(t...))%MOD;
}

int main() {
    int a, b, c; cin >> a >> b >> c;
    cout << mul(1000000000, 2, sum(a, b, -c)) << endl;
}