A8430. Steps

The first input line contains two integers $n$ and $m$ ( $1<=n,m<=10^{9}$ ) — the yard's sizes. The second line contains integers $x_{c}$ and $y_{c}$ — the initial square's coordinates ( $1<=x_{c}<=n,1<=y_{c}<=m$ ).

The third line contains an integer $k$ ( $1<=k<=10^{4}$ ) — the number of vectors. Then follow $k$ lines, each of them contains two integers $dx_{i}$ and $dy_{i}$ $(|dx_{i}|,|dy_{i}|<=10^{9},|dx|+|dy|>=1)$ .

Print the single number — the number of steps Vasya had made.

Please do not use the %lld specificator to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64d specificator.

In the first sample Vasya is initially positioned at square $(1,1)$ and makes $3$ steps by the first vector $(1,1)$ . So, he consecutively visits the squares $(2,2),(3,3),(4,4)$ . Then he makes $0$ steps by the second vector $(1,1)$ . He makes $1$ more step by the third vector $(0,-2)$ and he ends up in square $(4,2)$ . Overall, Vasya makes $4$ steps.

In the second sample Vasya is initially positioned in square $(1,2)$ and makes $0$ steps by vector $(-1,0)$ , as the square with coordinates $(0,2)$ is located outside the yard.

In the first sample Vasya is initially positioned at square $(1,1)$ and makes $3$ steps by the first vector $(1,1)$ . So, he consecutively visits the squares $(2,2),(3,3),(4,4)$ . Then he makes $0$ steps by the second vector $(1,1)$ . He makes $1$ more step by the third vector $(0,-2)$ and he ends up in square $(4,2)$ . Overall, Vasya makes $4$ steps.

In the second sample Vasya is initially positioned in square $(1,2)$ and makes $0$ steps by vector $(-1,0)$ , as the square with coordinates $(0,2)$ is located outside the yard.