Find Grade

#include<stdio.h>
int main()
{
    float m;
    printf("enter the marks");
    scanf("%f",&m);
    if(m>=80&&m<=100)
    {
        printf("the grade is A+");
    }
    else if(m>=70&&m<=79)
    {
        printf("the grade is A");
    }
    else if(m>=60&&m>=69)
    {
        printf("the grade is A-");
    }
    else if(m>=50&&m<=59)
    {
        printf("the grade is B");
    }
    else if(m>=40&&m<=49)
    {
        printf("the grade is C");
    }
    else
    {
        printf("the grade is fail");
    }
    //main();
    return 0;
}