Programs for Pincode, Gmail, and Mobile Number Validation

def verify_Gmail(Gmail):
    i=0
    while i<len(Gmail):
        current=Gmail[i]
        i+=1
        if current>="a" and current<="z":
            continue;
        elif current>="A" and current<="Z":
            continue;
        elif current>="0" and current<="9":
            continue;
        elif current=="@" or current=="." or current=="_":
            continue;
        else:
            return False
    if Gmail[-10:]=="@gmail.com":
        return True
    else:
        return False
if verify_Gmail(input("Enter Your Gmail :")):
    print("valid")
else:
    print("invalid") 

         pincode = int(input("Enter a pincode: "))

                count = 0
                temp = pincode

                while temp > 0:
                    temp = temp // 10
                    count += 1

                if count == 6 and pincode >= 100000 and pincode <= 999999:
                    print("YES")
                else:
                    print("NO")

 def mobile(n):
    i=0
    while i<len(n):
        if(n[i]>="0" and n[i]<="9") or (n[i]=="+") or (n[i]==" "):
            i+=1
        else:
            return "characters and special charactors not allowed"

    if len(n)==10:
        if n[0]>="6" and n[0]<="9":
            return "valid";
        else:
            return "First number should not be less then 6 "
    if len(n)==13:
        if n[0:3]=="+91":
            if n[3]>="6" and n[3]<="9":
                return "valid"
            else:
                return "Fourth number should not be less then 6"
        else:
            return "First three number should like +91"
    if len(n)==14:
        if n[0:4]=="+91 ":
            if n[4]>="6" and n[4]<="9":
                return "valid"
            else:
                return "fifth number should not be less then 6"
        return "First four number should like +91 "
    return "Please Enter Your valid Mobile Number"      
print(mobile(input("Enter Your Mobile  Number : ")));