diff --git a/credit.c b/credit.c
index 882037d..2b617e1 100644
--- a/credit.c
+++ b/credit.c
@@ -6,6 +6,7 @@ long long get_card_number(void);
 void find_issuer(long long card_number);
 int validate(long long card_number);
 int get_id(long long card_number);
+int get_length(long long card_number);
 
 int main(void)
 {
@@ -32,24 +33,24 @@ long long get_card_number()
 
 void find_issuer(long long card_number)
 {
-    int id = get_id(card_number);
+    int id = get_id(card_number), count = get_length(card_number);
 
-    // Number beginning with 34 or 37
-    if (id / 100 == 34 || id / 100 == 37)
+    // Number beginning with 34 or 37 and length is 15
+    if ((id / 100 == 34 || id / 100 == 37) && count == 15)
     {
         printf("AMEX\n");
         return;
     }
 
-    // Number beginning with 4
-    if (id / 1000 == 4)
+    // Number beginning with 4 and length is 13 or 16
+    if ((id / 1000 == 4) && (count == 13 || count == 16))
     {
         printf("VISA\n");
         return;
     }
 
-    // Number beginning with 51-55 or 2221-2720
-    if ((id / 100 >= 51 && id / 100 <= 55) || (id >= 2221 && id <= 2720))
+    // Number beginning with 51-55 or 2221-2720 and length is 16
+    if (((id / 100 >= 51 && id / 100 <= 55) || (id >= 2221 && id <= 2720)) && count == 16)
     {
         printf("MASTERCARD\n");
         return;
@@ -108,17 +109,9 @@ int validate(long long card_number)
 
 int get_id(long long card_number)
 {
-    int count = 0, id;
+    int count = get_length(card_number), id;
     long long n, trunc = 1;
 
-    n = card_number;
-
-    while (n > 0)
-    {
-        n /= 10;
-        count++;
-    }
-
     if (count < 13 || count > 16)
     {
         return 0;
@@ -131,3 +124,15 @@ int get_id(long long card_number)
     id = card_number / trunc;
     return id;
 }
+
+int get_length(long long card_number)
+{
+    int count = 0;
+
+    while (card_number > 0)
+    {
+        card_number /= 10;
+        count++;
+    }
+    return count;
+}