Automating signup by slightly changing username

so my code is below… i have no idea how to modify this… i would like to take the email address

ddsdmm.attcap1(at)manyme(dot)com and i want to run this macro 30 times in a loop and each sucessive time it runs i want the email address to change either by adding a random 3 digit number or incrementing the number by one so the 2nd loop email address used is

ddsdmm.attcap2(at)manyme(dot)com etc… how can I achieve this?

i am open to the least complicated way possible … if generating a CSV with usernames is easiest that is fine… whatever is best

{
“Command”: “type”,
“Target”: “id=first-name”,
“Value”: “greg”,
“Targets”: [
“id=first-name”,
“name=firstName”,
“xpath=//[@id=“first-name”]",
“xpath=//input[@id=‘first-name’]”,
“xpath=//input”,
“css=#first-name”
],
“Description”: “”
},
{
“Command”: “type”,
“Target”: “id=last-name”,
“Value”: “moore”,
“Targets”: [
“id=last-name”,
“name=lastName”,
"xpath=//
[@id=“last-name”]”,
“xpath=//input[@id=‘last-name’]”,
“xpath=//div[2]/div/div/input”,
“css=#last-name”
],
“Description”: “”
},
{
“Command”: “click”,
“Target”: “id=email-address-new-user”,
“Value”: “”,
“Targets”: [
“id=email-address-new-user”,
“name=email”,
“xpath=//[@id=“email-address-new-user”]",
“xpath=//input[@id=‘email-address-new-user’]”,
“xpath=//div[3]/div/div/input”,
“css=#email-address-new-user”
],
“Description”: “”
},
{
“Command”: “type”,
“Target”: “id=email-address-new-user”,
“Value”: “dsddmm.attcap1@manyme.com”,
“Targets”: [
“id=email-address-new-user”,
“name=email”,
"xpath=//
[@id=“email-address-new-user”]”,
“xpath=//input[@id=‘email-address-new-user’]”,
“xpath=//div[3]/div/div/input”,
“css=#email-address-new-user”
],
“Description”: “”
},
{
“Command”: “click”,
“Target”: “xpath=//[@id="__next"]/div",
“Value”: “”,
“Targets”: [
"xpath=//
[@id=”__next"]/div",
“xpath=//div[2]/div”,
“css=#__next > div.MuiContainer-root.MuiContainer-maxWidthMd”
],
“Description”: “”
},

Basically your question is how to increment (add) numbers