H, W, Q = map(int, input().split()) from collections import defaultdict min_y = defaultdict(int) ans = H*W for _ in range(Q): y, x = map(int, input().split()) if x not in min_y: ans -= H - y +1 min_y[x] = y else: ans -= min_y[x] - min(min_y[x], y) min_y[x] = min(min_y[x], y) print(ans)