#D7601. Sandglass2
Sandglass2
Sandglass2
We have a sandglass that runs for X seconds. The sand drops from the upper bulb at a rate of 1 gram per second. That is, the upper bulb initially contains X grams of sand.
How many grams of sand will the upper bulb contains after t seconds?
Constraints
- 1≤X≤10^9
- 1≤t≤10^9
- X and t are integers.
Input
The input is given from Standard Input in the following format:
X t
Output
Print the number of sand in the upper bulb after t second.
Examples
Input
100 17
Output
83
Input
48 58
Output
0
Input
1000000000 1000000000
Output
0
inputFormat
Input
The input is given from Standard Input in the following format:
X t
outputFormat
Output
Print the number of sand in the upper bulb after t second.
Examples
Input
100 17
Output
83
Input
48 58
Output
0
Input
1000000000 1000000000
Output
0
样例
48 580