pangram program in c

1//Pangram is string that contains all the alphabets in it
2#include<stdio.h>
3#include<ctype.h>
4
5int main() {
6    int arr[91]={0}, flag = 1;
7    char c;
8    while(scanf("%c",&c)==1){
9        c = toupper(c);
10        arr[(int)c]++;
11    }
12    for(int i=65; i<91;i++){
13        if(arr[i]==0)
14        flag = 0;
15    }
16    
17    if(flag)printf("panagram");
18    else printf("not panagram");
19    
20    return 0;
21}