只能过subtask1，#6 #8 #9 #10都TLE超时了（已经用了快读快写）

#include<cstdio>
inline long long read(){
    long long s=0;
    char ch=getchar();
    while(ch<'0' or ch>'9'){
        ch=getchar();
    }
    while(ch>='0' and ch<='9'){
        s=s*10+ch-48;
        ch=getchar();
    }
    return s;
}
inline void write(long long a){
    if(a>=10){
        write(a/10);
    }
    putchar(a%10+'0');
}
int main(){
    register long long n=read(),m=read(),k=read(),a1=n,a2=m,t;
    for(register long long i=3;i<=k;i++){
        t=a2;
        a2=(a1*a2)%10;
        a1=t;
    }
    write(a2);
    return 0;
}