Please any one give Explanation [Resolved]

string  str1="Gowthaman");
string index = str1.IndexOf("m").ToString(); ;
 Console.WriteLine(index);

here i find out "m" position so use str1.IndexOf("m") i get out put for 6 but in that name m' th position 7 any one tell me It.s correct or not

gowthaman8870226416 [Resolved]