CF465A.inc ARG

Sergey is testing a next-generation processor. Instead of bytes the processor works with memory cells consisting of n bits. These bits are numbered from 1 to n. An integer is stored in the cell in the following way: the least significant bit is stored in the first bit of the cell, the next significant bit is stored in the second bit, and so on; the most significant bit is stored in the n-th bit.

Now Sergey wants to test the following instruction: "add 1 to the value of the cell". As a result of the instruction, the integer that is written in the cell must be increased by one; if some of the most significant bits of the resulting number do not fit into the cell, they must be discarded.

Sergey wrote certain values of the bits in the cell and is going to add one to its value. How many bits of the cell will change after the operation?

谢尔盖正在测试一款下一代处理器。该处理器不使用字节，而是使用由 n 个比特组成的内存单元。这些比特编号为 1 到 n。一个整数以如下方式存储在该单元中：最低有效位（LSB）存储在单元的第 1 个比特中，次低有效位存储在第 2 个比特中，依此类推；最高有效位（MSB）存储在第 n 个比特中。

现在，谢尔盖希望测试如下指令：“将单元的值加 1”。执行该指令后，单元中存储的整数必须增加 1；若结果数值的某些最高有效位无法容纳进该单元，则这些位必须被丢弃。

谢尔盖已在单元中写入了某些比特值，并准备对其执行加 1 操作。请问：该操作执行后，单元中有多少个比特会发生改变？

The first line contains a single integer n (1 ≤ n ≤ 100) — the number of bits in the cell.

The second line contains a string consisting of n characters — the initial state of the cell. The first character denotes the state of the first bit of the cell. The second character denotes the second least significant bit and so on. The last character denotes the state of the most significant bit.

第一行包含一个整数 $n$（$1 \leq n \leq 100$）—— 表示该单元中比特位的数量。

第二行包含一个由 $n$ 个字符组成的字符串 —— 表示该单元的初始状态。第一个字符表示该单元第一个比特位的状态；第二个字符表示第二低位比特位的状态，依此类推；最后一个字符表示最高位比特位的状态。

Print a single integer — the number of bits in the cell which change their state after we add 1 to the cell.

输出一个整数——对单元格加 1 后，状态发生改变的比特位数量。

In the first sample the cell ends up with value 0010, in the second sample — with 0000.

在第一个样例中，该单元格最终的值为 $0010$，在第二个样例中为 $0000$。