create dev channel

zeta/py/completed/1931.py

@@ -0,0 +1,13 @@
+N = int(input())
+I = [tuple(map(int, input().split())) for _ in range(N)]
+
+I.sort(key=lambda x: (x[1], x[0]))
+
+last = 0
+cnt = 0
+for i in range(N):
+    if last <= I[i][0]:
+        last = I[i][1]
+        cnt += 1
+
+print(cnt)