All test case not passing

#1

can you help?
the formula i used seem to work for all examples i took but still some test cases are not passing.
Can you give a value of a,b,c for which this formula doesnt work.

#2

u have multiplied the power , u need to make a loop and multiply inside the loop

int a  ,  b  , c;
        cin>>a>>b>>c;
        for(int i=1;i <= b;i++)
        {
            a *= a;
            a %= c;
        }
        cout<<a%c<<endl;