题解

extern "C" int scanf(const char*,...) noexcept; //使用scanf
extern "C" int putchar(int) noexcept; //使用putchar
extern "C" int main() noexcept{
    int n;
    static char s[101]; //static: 静态栈
    scanf("%d%s",&n,s);
    for(char* it=s;*it!='\0';it++){ //遍历
        putchar((*it-'a'+n)%26+'a'); //算法
    }
}