#include<bits/stdc++.h>
using namespace std;
#define ll long long
bool jz(ll a, ll b, ll d, ll c) {
	ll num = 0, asd = 0, fgh = 0, i = 0;
	while (a) {
		num = num + a % 10 * int(pow(c, i));
		i++;
		a /= 10;
	}
	i = 0;
	while (b) {
		asd = asd + b % 10 * int(pow(c, i));
		i++;
		b /= 10;
	}
	i = 0;
	while (d) {
		fgh = fgh + d % 10 * int(pow(c, i));
		i++;
		d /= 10;
	}
	if (num * asd == fgh) {
		return 1;
	}
	else {
		return 0;
	}
}
int main() {
	ll a, b, c;
	bool n = 0;
	cin >> a >> b >> c;
	for (ll i = 1; i <= 1000000; i++) {
		if (jz(a, b, c, i) == 1) {
			cout << i;
			n = 1;
			return 0;
		}
	}
	if (n == 0) {
		cout << 0;
	}
	return 0;
}