#include #define REP(i,n) for(int i=0,i##_len=(n);i>N; vector P(N); REP(i,N) cin>>P[i]; ll ans=1; REP(i,N){ ll q=P[i]; ll d=0; while(q){ d+=q%10; q/=10; } d%=9; ans*=d; ans%=9; } cout<<(ans?ans:9)<