import std.stdio, std.algorithm, std.string, std.string, std.conv, std.array, std.range, std.math;

long A, B, C;
bool can(long age) {
    long x = age / A;
    long y = age - x;
    return x * B + y >= C;
}

void main() {
    auto input = readln.split.to!(long[]);
    A = input[0]; B = input[1]; C = input[2];

    long lb = -1, ub = 10L^^18;
    while (ub - lb > 1) {
        long mid = (lb + ub) / 2;
        if (can(mid)) ub = mid;
        else lb = mid;
    }
    writeln(ub);

    string _ = readln(); // dbg
}