Prime Number Determination

Problem description

For the expression n ^ 2 + N + 41, when n is in the range of (x, y), an integer (including X and Y) is obtained) (-39 <= x <Y <= 50), determines whether the value of this expression is a prime number.

 

Input

There are multiple groups of input data. Each group occupies one row and consists of two integers x and y. When x = 0 and Y = 0, the input is complete and the row is not processed.

 

Output

For values in each given range, if the expression value is a prime number, "OK" is output; otherwise, "sorry" is output, and each group of output occupies one row.

 

Sample Input

0 1

0 0

 

Sample output

OK

 

 1 #include <stdio.h> 2 #include <string.h> 3 #include <math.h> 4 #define N 3000 5   6 int main(){ 7     char flag[N]; 8     int i; 9     int j;10     int a;11     int b;12     int mark;13     int temp;14      15     memset(flag,‘0‘,N);16     flag[0]=‘1‘;17     flag[1]=‘1‘;18      19     for(i=2;i<=sqrt(N);i++){20         if(flag[i]==‘0‘){21             for(j=i*i;j<N;j+=i)22                 flag[j]=‘1‘;23         }24     }25      26     while(1){27         mark=0;28         scanf("%d%d",&a,&b);29          30         if(a==0 && b==0)31             break;32              33         for(i=a;i<=b;i++){34             if(flag[i*i+i+41]!=‘0‘)35                 mark=1;36         }37          38         if(mark==1)39             printf("Sorry\n");40              41         else42             printf("OK\n");43              44     }45      46     return 0;47 }

 

Prime Number Determination