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#include <stdio.h> int is_prime(unsigned int n){ int i=1; if(!(n&1)) return 0; if (n==1 || n==2 || n==3) return 1; do{ i+=2; if(!(n%i)) return 0; }while(i*i<=n); return 1; } int main(){ printf(is_prime(5)?"prime":"not prime"); return 0; }
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prime