제출


int a;m(d){return a=d?(d&1?a:1)*(d=m(d/2))*d%_10:1;}

main(b,c){scanf("%d",&c);while(c--)scanf("%d%d",&a,&b),printf("%d ",m(b)?a:10);}


https://www.acmicpc.net/problem/1009


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왜 안되는지...