#include //#include using namespace std; //using namespace atcoder; typedef long long ll; typedef pair P; //typedef modint998244353 mint; int a,b,c; int ans=1000000000; int main(void){ cin.tie(0); ios::sync_with_stdio(0); cin>>a>>b>>c; if(a+b<=c){ if(b>0&&c-(a+b)<=9){ cout<<9-(c-(a+b))<