Cities and roads
In the galaxy of "Milky Way" on the planet "Neptune" has N cities, some of which are connected by roads. Emperor "Maximus" Galaxy "Milky Way" has decided to make an inventory of roads on the planet "Neptune". But as it turned out he was not good at math, so he asks you to count the number of roads.
Specifications
Input
The first line contains the number N (0 ≤ N ≤ 100). In the next N lines contain the N numbers, each of which is the identity or zero. Moreover, if the position (i, j) square matrix is one, then the i-th and j-th city are connected by roads, and if zero, it is not connected.
Output
Derive a single number - the number of roads on the planet "Neptune".
Problem information
Time Limit: 1 secondsMemory Limit: 64 MB
Balls for the passed test: 10
Complexity: 3% 221/229
Classes: Graph theory
Example
Example input5 0 1 0 0 0 1 0 1 1 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 |
Example output3 |
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