Number of times a substring occurs in a string

#Program to find the number of times a substring occurs in a given string
text=raw_input("Enter the text:")
count=0
length=len(text)
for i in range(0,length):
    if text[i]=='E' and text[i+1]=='A' and text[i+2]=='T':
        count+=1
print count
raw_input()