Retina, 44 20 bytes

_{Crossed out 44 is still regular 44 :(}

+`'(\w).(.*).\B
$1$2

Assumes input in following format (in unary - counting character: '):
{number of repeats}{string}
For example: '''''''ABCDEFGHIJKLMNOP
There is no space between number of repeats and the string.

Thanks @MartinBüttner for shaving off 24 bytes!

Try it online!

Retina, 44 20 bytes

_{Crossed out 44 is still regular 44 :(}

+`'(\w).(.*).\B
$1$2

Assumes input in following format (in unary - counting character: '):
{number of repeats}{string}
For example: '''''''ABCDEFGHIJKLMNOP
There is no space between number of repeats and the string.

Thanks @MartinBüttner for shaving off 24 bytes!

Try it online!

Retina, 44 20 bytes

+`'(\w).(.*).\B
$1$2

Assumes input in following format (in unary - counting character: '):
{number of repeats}{string}
For example: '''''''ABCDEFGHIJKLMNOP
There is no space between number of repeats and the string.

Thanks @MartinBüttner for shaving off 24 bytes!

Try it online!

Retina, 44 20 bytes

_{Crossed out 44 is still regular 44 :(}

+`'(\w).(.*).\B
$1$2

Assumes input in following format (in unary - counting character: '):
{number of repeats}{string}
For example: '''''''ABCDEFGHIJKLMNOP
There is no space between number of repeats and the string.

Thanks @MartinBüttner for shaving off 24 bytes!

Try it online!

Retina, 44 22 bytes

+`'([^']).(.*).\B
$1$2

Assumes input in following format (in unary - counting character: '):
{number of repeats}{string}
For example: '''''''ABCDEFGHIJKLMNOP
There is no space between number of repeats and the string.

Thanks @MartinBüttner for shaving off 22 bytes!

Try it online!

Retina, 44 20 bytes

+`'(\w).(.*).\B
$1$2

Assumes input in following format (in unary - counting character: '):
{number of repeats}{string}
For example: '''''''ABCDEFGHIJKLMNOP
There is no space between number of repeats and the string.

Thanks @MartinBüttner for shaving off 24 bytes!

Try it online!