/* int %d longlong %lld float %f double %lf char %c char[] %s 'a'=97 'z'=122 'A'=65 'Z'=90 '0'=48 '9'=57 */ #include #include #include #include #include #include using namespace std; const int N=1e5+10; const int INF=0x3f3f3f3f; int n,x,y,a[N],b[N],c[N]; int len; int main(){ scanf("%d",&n); for(int i=1;i<=n;i++){ scanf("%d%d",&x,&y); a[n-i]=x; b[n-i]=y; } x=0; for(int i=0;i<n;i++){ c[i]=a[i]+b[i]+x; x=c[i]/10; c[i]%=10; } len=n-1; if(x){ c[++len]=x; } for(int i=len;i>=0;i--){ printf("%d",c[i]); } return 0; }