Write a Ruby program to check three given integers and return their sum

def check_num(a, b, c)
    if a==b && b==c
        return 0
    elsif a==b
        return c
    elsif a==c
        return b
    elsif b==c
        return a
    else
        return a+b+c
    end
end
print check_num(5, 5, 5),"\n"
print check_num(5, 5, 7),"\n"
print check_num(5, 7, 5),"\n"
print check_num(7, 5, 5),"\n"
print check_num(1, 2, 3),"\n"