#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pll> pip;
const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-9;

ll b[3];

int main() {
	REP(i, 3) cin >> b[i];
	
	for (int i = -10000000; i <= 10000000; i++) {
		ll r = i;
		ll d = 10 * b[1] - r * b[0];
		
		ll tmp = r * b[1] + d;
		if (tmp != b[2] * 10) continue;
		
		ll ans = r * b[2] + d;
		if (ans % 10 != 0) continue;
		ans /= 10;
		
		printf("%lld\n", ans);
		break;
	}
	
	return 0;
}