Construct a valid JSON object from the following three strings.
key1, value1
key2, value2
key3, value3
```
{
  "key1": "value1",
  "key2": "value2",
  "key3": "value3"
}
```
Complete the following task based on the instruction and optional input provided.### Instruction:
Construct a valid JSON object from the following three strings.

### Input:
key1, value1
key2, value2
key3, value3

### Output:
```
{
  "key1": "value1",
  "key2": "value2",
  "key3": "value3"
}
```