I submitted my code in python of WITMATH during the contest and got AC. When i was submitting the same using C++ it was giving TLE though i had taken all steps to prevent overflow. Please can anyone help. Here's my code : /aayushagarwal/

include<cstdio>

include<cstdlib>

using namespace std; unsigned long long int mult(unsigned long long int a,unsigned long long int b,unsigned long long int c) { unsigned long long int x=0,y=a%c; while(b>0) { if(b%2==1) {x=x+y; if(x>c)x=x%c; } y=y+y; if(y>c)y=y%c; b/=2; } return x%c; } unsigned long long int modulo( unsigned long long int a, unsigned long long int b, unsigned long long int c) { unsigned long long int x = 1; unsigned long long int y = a; while (b>0) { if (b%2==1) x = mult(x,y,c); y = mult(y,y,c); b = b/2;

    }

return x%c; }

bool millerRabin(unsigned long long int N,unsigned long long int iteration) { if (N<2) return false; if (N!=2&&N%2==0) return false;

   unsigned  long long int d=N-1;
    while (d%2==0)
            d = d/2;

    for (long long int i=0;i<iteration;i++)
    {

            unsigned long long int  a = rand()%(N-1)+1;
            unsigned long long int temp = d;
            unsigned long long int x = modulo(a,temp,N);
            while (temp!=N-1 && x!=1 and x!=N-1){
                    x = mult(x,x,N);
                    temp = temp*2;
                    }

            if (x!=N-1 && temp%2==0)
                    return false;

                }
                return true;
                }
                int main()
                {   
                    unsigned long long int n;int t;

                    scanf("%d",&t);
                    while(t--)
                    {
                    bool prime=false;
                    scanf("%llu",&n);
                    if(n==2||n==3)
                    printf("%llu\n",n);
                    else if(n==4)
                    printf("3\n");
                    else if(n==5||n==6)
                    printf("5\n");
                    else if(n==7||n==8||n==9||n==10)
                    printf("7\n");
                    else if(n==11||n==12)
                    printf("11\n");

                    else
                    {
                        while(!prime)
                    {       
                            if(n%2!=0 && n%3!=0 && n%5!=0 && n%7!=0 && n%11!=0)
                            prime=millerRabin(n,20);
                            n--;
                            }
                            printf("%llu\n",n+1);
                            }
                            }

                            return 0;
                            }