import math
import statistics
import sys
import copy
sys.setrecursionlimit(int(1e8))

n,m,t = list(map(int,input().split()))

s = [[0]*n for i in range(t+2)]

s1 = [[0]*n for i in range(t+1)]
for i in range(m):
    t,d = list(map(int,input().split()))
    s1[t][d-1] += 1

for i in range(t+1):
    for j in range(n):
            if s1[i][j] !=0:
                s[i+1][j] = s[i][j]+s1[i][j]*2
            else:
                if s[i][j] != 0:
                    s[i+1][j] = s[i][j]-1
                else:
                    s[i+1][j] = 0
ans = 0

for i in range(n):
    if s[t+1][i]>5:
        ans += 1

print(ans)